Tai Chi for balance and postural control in people with peripheral neuropathy: A scoping review.

BACKGROUND: Peripheral neuropathy can affect balance and increase fall risk. Tai Chi is known to activate neuromuscular systems and may help improve balance and postural control. We conducted a scoping review of clinical studies that evaluated the impact of Tai Chi on balance and related neurobiological outcomes among individuals with peripheral neuropathy. METHODS: We systematically searched three databases from inception to December 19, 2023 and identified 11 eligible clinical studies. We extracted trial information from each study and performed a qualitative study features analysis to summarize the clinical evidence and neurobiological mechanisms of Tai Chi in regulating balance among people with peripheral neuropathy. RESULTS: We found that among 508 participants with clinical peripheral neuropathy, Tai Chi significantly improved single leg stance, 6-min walk, timed up-and-go tests, and gait speed when measured pre- and post-exercise. However, the differences between Tai Chi and sham exercise control that involved active calisthenics and stretching exercises were not statistically significant. Studies that used quantitative sensory testing showed that Tai Chi was associated with significant increases in plantar vibration and tactile sensitivity. The effect of Tai Chi on postural control varied depending on plantar sensory loss status, and results on muscle strength remained mixed. Other neurobiological effects involve strengthening muscle performance and proprioception and consolidating cognitive awareness of walking strategy and practical behavioral techniques. CONCLUSIONS: The findings indicated that Tai Chi may enhance balance, postural control, and gait speed in patients with peripheral neuropathy, possibly through sensory restoration, although further research is needed to confirm this. Whether Tai Chi improves muscle strength or other gait health parameters is inconclusive. Rigorous randomized clinical trials should be conducted to determine the effect of Tai Chi on balance in this population by measuring functional balance and quantitative sensory outcomes.

Heart rate variability during sleep onset in patients with insomnia with or without comorbid sleep apnea.

OBJECTIVES: Pre-sleep stress or hyperarousal is a known key etiological component in insomnia disorder. Despite this, physiological alterations during the sleep onset are not well-understood. In particular, insomnia and obstructive sleep apnea (OSA) are highly prevalent co-morbid conditions, where autonomic regulation may be altered. We aimed to characterize heart rate variability (HRV) during sleep onset as a potential measure of pre-sleep hyperarousal. METHODS: We described the profile of pre-sleep HRV measures and explore autonomic differences in participants with self-reported insomnia disorder (with no OSA, n = 69; with mild OSA, n = 70; with moderate or severe OSA, n = 66), compared to normal sleep controls (n = 123). Heart rate data during the sleep onset process were extracted for HRV analyses. RESULTS: During the sleep onset process, compared to normal sleep controls, participants with insomnia had altered HRV, indicated by higher heart rate (p = 0.004), lower SDNN (p = 0.003), reduced pNN20 (p < 0.001) and pNN50 (p = 0.010) and lower powers (p < 0.001). Participants with insomnia and moderate/severe OSA may have further deteriorated HRV outcomes compared to no/mild OSA patients with insomnia but differences were not significant. Insomnia itself was associated with significantly higher heart rate, lower pNN20, and lower high frequency power even after adjustment for age, gender, BMI and OSA severity. CONCLUSIONS: Participants with insomnia had lower vagal activity during the sleep onset period, which may be compounded by OSA, reflected in higher heart rates and lower HRV. These altered heart rate dynamics may serve as a physiological biomarker for insomnia during bedtime wakefulness, or as a potential tool to evaluate the efficacy of behavioral interventions which target bedtime stress.

Integrating Chiropractic Care and Tai Chi Training for the Treatment of Chronic Nonspecific Neck Pain in Nurses: A Single-Arm Mixed-Methods Pilot Trial.

Objectives: Chronic nonspecific neck pain (CNNP) is prevalent among health care workers, with particularly high rates among nurses. Nurses experiencing CNNP often report decreased job satisfaction, increased absenteeism, and reduced productivity. In recent years, nonpharmacologic approaches have gained attention as effective treatments for the management of CNNP, with exercise and manual therapies representing two of the most common. Early evidence shows that multimodal treatments may be more effective than unimodal strategies. The purpose of this current study was to assess the feasibility and observe the clinical outcomes of combined multimodal chiropractic care (MCC) and Tai Chi (TC) for CNNP in nurses. Methods: A single-arm mixed-methods pilot trial was conducted including 16 weeks of MCC and TC in nurses with self-reported CNNP. Feasibility outcomes were recruitment, retention, and adherence to the interventions. Clinical outcomes of interest included neck pain and related disabilities. Secondary outcomes of interest were functional, affective, and work-related performance. Qualitative interviews were also conducted. Results: Of the 59 screened, 36 met the eligibility criteria, and 21 were enrolled. The retention rate was 71.4%, and adherence rates were 85.3% for MCC and 62.5% for TC classes. Multiple pain and disability-related outcomes exhibited modest improvement from baseline to 16-week follow-up. Qualitative analysis identified six emergent themes: (1) neck pain being an inherent part of nursing, (2) nurses push through their pain, (3) MCC relieves pain and is instructive for preventing pain, (4) TC provides overall relaxation, (5) both interventions increased body awareness and improved posture, and (6) scheduling difficulties were a key obstacle for participating. Conclusions: Observed reductions in neck pain and disability suggest the potential utility of combined MCC and TC interventions for managing CNNP. Along with qualitative feedback regarding facilitators and barriers to participation, the findings support and inform a future randomized trial evaluating the combined benefits of MCC and TC for CNNP in nurses. Clinical Trial Registration #NCT06523036.

Oxylipin Dynamics Following A Single Bout of Yoga Exercise: A Pilot Randomized Controlled Trial Secondary Analysis.

Background: Yoga may promote health via a complex modulation of inflammation. Little is known about oxylipins, a class of circulating mediators involved in inflammation resolution. Objective: To explore the acute effects of yoga exercise on systemic levels of oxylipins. Methods: This is a secondary analysis of a three-arm (high-intensity-yoga: HY, n = 10); moderate-intensity-yoga: MY, n = 10; and no-intervention-control: CON, n = 10) pilot randomized controlled trial employing a single bout of yoga exercise. Blood samples (baseline and 4-timepoint post-intervention) were used for an unbiased metabolipidomic profiling analysis. Net Areas Under the Curve per oxylipin were evaluated for each group. Results: Lipoxin(LX)B4, prostaglandin(PG)D2, and resolvin(Rv)D3 exhibited a greater magnitude of change in HY compared with MY and CON. Conclusion: Findings inform the design of future trials exploring the acute effects of yoga exercise on oxylipins' systemic levels.

Acupoint Sensitivity in Health and Disease: A Systematic Review.

Introduction: The concept of acupoints is a key defining feature of acupuncture, yet the scientific basis of acupoints remains unclear. In recent years, there has been an emerging body of animal studies demonstrating an association between cutaneous sensitivity and visceral pathophysiology, through which acupoints over the skin are sensitized in pathologic conditions. Several studies with humans have also been conducted to assess whether the sensitivity of acupoints is distinct in healthy versus clinical populations. However, no systematic review has been conducted to collate and synthesize the status and quality of human studies on this topic. Methods: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). Literature search was performed by combining variations of search terms related to acupoints and pain sensitivity in PubMed, EMBASE, and Alt HealthWatch (EBSCOHost). Screening of titles and abstracts and review of full-text articles for eligibility were performed by two independent investigators. Using a predefined template, information on subject characteristics, pathologic conditions, names of assessed acupoints, and relevant main findings were extracted from the included studies. The methodological quality of included studies was assessed using a modified Newcastle-Ottawa Scale (NOS) for case-control studies. A quality assessment checklist was also developed by the present authors to examine the quality of reporting of experimental variables that were considered important for evaluating acupoint sensitivity. Results: A total of 3453 studies were identified from the database search, of which 11 met the eligibility criteria to be included in this review. Six studies examined the mechanical sensitivity of body acupoints, and the remaining five studies examined the mechanical sensitivity of auricular points. Overall, findings suggest that the sensitivity of acupoints may be distinct in healthy versus clinical populations. However, there were various potential sources of bias and substantial heterogeneity across included studies in clinical conditions and acupoints. Conclusion: There is at present insufficient evidence to support or refute that acupoints in humans are sensitized in pathologic conditions. There were various methodological issues, including small sample size and poor reporting of experimental design and variables, which limit the ability to draw a definitive conclusion on this topic. It is also largely unclear whether it is the general body regions rather than specific acupoints that may be sensitized, as most studies did not include nonacupoint location(s) for comparison. Thus, further rigorous research is warranted.

The impact of yoga on aging physiology: A review.

Frailty represents diminished reserve across multiple physiologic systems, accompanied by increased vulnerability to stressors and increased morbidity and mortality. With population aging, strategies to prevent and manage frailty are priorities in clinical medicine and public health. Current evidence-based approaches to frailty management are multimodal in nature. Yoga, an increasingly popular and highly adaptable mind-body practice, is multi-component, incorporating physical postures, breathing practices, meditation, and other elements, and may be a strategy for frailty management. Here, we summarize the evidence linking yoga practice to mitigation of age-related degradation across multiple physiologic systems, including cardiovascular, pulmonary, musculoskeletal, and nervous systems. We discuss putative mechanisms of action including modulation of the hypothalamic-pituitary-adrenal axis. Finally, we consider implications for clinical practice and future research.

Prepandemic Physical Activity and Risk of COVID-19 Diagnosis and Hospitalization in Older Adults.

Importance: Higher prepandemic physical activity (PA) levels have been associated with lower risk and severity of COVID-19. Objective: To investigate the association between self-reported prepandemic PA levels and the risk and severity of COVID-19 in older US adults. Design, Setting, and Participants: This cohort study combined cohorts from 3 ongoing prospective randomized clinical trials of US adults aged 45 years or older who provided prepandemic self-reports of baseline leisure-time PA and risk factors for COVID-19 outcomes using the most recent questionnaire completed as of December 31, 2019, as the baseline PA assessment. In multiple surveys from May 2020 through May 2022, participants indicated whether they had at least 1 positive COVID-19 test result or were diagnosed with or hospitalized for COVID-19. Exposure: Prepandemic PA, categorized into 3 groups by metabolic equivalent hours per week: inactive (0-3.5), insufficiently active (>3.5 to <7.5), and sufficiently active (≥7.5). Main Outcome and Measures: Primary outcomes were risk of COVID-19 and hospitalization for COVID-19. Multivariable logistic regression was used to estimate odd ratios (ORs) and 95% CIs for the association of COVID-19 diagnosis and/or hospitalization with each of the 2 upper PA categories vs the lowest PA category. Results: The pooled cohort included 61 557 participants (mean [SD] age, 75.7 [6.4] years; 70.7% female), 20.2% of whom were inactive; 11.4%, insufficiently active; and 68.5%, sufficiently active. A total of 5890 confirmed incident cases of COVID-19 were reported through May 2022, including 626 hospitalizations. After controlling for demographics, body mass index, lifestyle factors, comorbidities, and medications used, compared with inactive individuals, those insufficiently active had no significant reduction in infection (OR, 0.96; 95% CI, 0.86-1.06) or hospitalization (OR, 0.98; 95% CI, 0.76-1.28), whereas those sufficiently active had a significant reduction in infection (OR, 0.90; 95% CI, 0.84-0.97) and hospitalization (OR, 0.73; 95% CI, 0.60-0.90). In subgroup analyses, the association between PA and SARS-CoV-2 infection differed by sex, with only sufficiently active women having decreased odds (OR, 0.87; 95% CI, 0.79-0.95; P = .04 for interaction). Conclusions and Relevance: In this cohort study of adults aged 45 years or older, those who adhered to PA guidelines before the pandemic had lower odds of developing or being hospitalized for COVID-19. Thus, higher prepandemic PA levels may be associated with reduced odds of SARS-CoV-2 infection and hospitalization for COVID-19.

Holistic frailty prevention: The promise of movement-based mind-body therapies.

Aging is characterized by fundamental cellular and molecular hallmarks that result in physiologic decline of most body systems. This may culminate in frailty, a state of decreased reserve. Because frailty is a state of multisystem dysregulation, multimodal interventions may be necessary to mitigate and prevent progression rather than interventions targeting a single system. Movement-based mind-body therapies, such as tai chi and yoga, are promising multimodal strategies for frailty prevention and treatment given their inherent multicomponent nature. In this review, we summarize the links between hallmarks of aging and frailty and how tai chi and yoga may impact these hallmarks. We review trial evidence for the impact of tai chi and yoga on frailty in older populations and discuss opportunities for future research.

Long-term Tai Chi practice in older adults is associated with "younger" functional abilities.

Age-related alterations in physiology lead to declines in physical function that are associated with numerous adverse outcomes among older adults. Utilizing a hybrid design, we aimed to understand whether both long-term and short-term Tai Chi (TC) training are associated with age-related decline in physical function in healthy older adults. We first conducted cross-sectional comparisons among TC-naïve older adults (n = 60, 64.2 ± 7.7 years), TC-expert older adults (n = 27, 62.8 ± 7.6 years, 24.5 ± 12 years experience), and TC-naïve younger adults (n = 15, 28.7 ± 3.2 years) to inform long-term effects of TC training on physical function, including single leg stance time with eyes closed, grip strength, Timed Up and Go, maximum walking speed, functional reach, and vertical jump for lower-extremity power. There were significant differences among the three groups on all the six tests. For most functional tests, TC-experts performed better than age-matched TC-naïve controls and were statistically indistinguishable from young healthy adult controls. Long-term TC training was associated with higher levels of physical function in older adults, suggesting a potential preventative healthy aging effect. In the randomized longitudinal trial, TC-naïve subjects were randomized (n = 31 to Tai Chi group, n = 29 to usual care control group) to evaluate the short-term effects of TC over 6 months on all outcomes. TC's short-term impacts on physical function were small and not statistically significant. The impact of short-term training in healthy adults is less clear. Both potential longer-term preventive effects and shorter-term restorative effects warrant further research with rigorous, adequately powered controlled clinical trials.

A Web-Based Mind-Body Intervention (Mindful Steps) for Promoting Walking in Chronic Cardiopulmonary Disease: Insights From a Qualitative Study.

Background: Given the deleterious effects of physical inactivity in persons with chronic obstructive pulmonary disease (COPD) and/or heart failure (HF), interventions that promote long-term daily physical activity are needed. Mindful Steps, designed to promote walking behaviors in COPD and HF, is a multicomponent intervention that integrates mind-body content with other self-regulatory components. The aim of the current qualitative study was to characterize participants' experiences with Mindful Steps and understand the perceived influence of the intervention on walking and health. Method: In the context of a pilot randomized controlled feasibility trial comparing the year-long Mindful Steps program to usual care among individuals with COPD and HF, semi-structured qualitative interviews were administered at 6- and 12-months. Interviews were audio recorded and transcribed. The constant comparative method was used to code transcripts, identify categories, and develop interrelated themes. Results: Nineteen participants (63% female; Mage = 70.2 years, SD = 6.95) who were randomized to the intervention group completed the 6-month interview and 17 completed the 12-month interview. The pedometer with feedback, live group classes, and mind-body videos were described as the most helpful intervention components. Participants learned several strategies that helped their walking (e.g., breathing regulation and awareness, body awareness, mind-body techniques, pacing), described walking as enjoyable, and identified internal reasons for walking (e.g., to feel good). They also reported several physical and mental health benefits of the intervention. Some participants reported limited influence of the intervention on walking or health. Many participants continued to use the strategies they learned in the first half of the intervention at 12-months. Conclusions: The mind-body content of Mindful Steps appeared to positively influence walking behaviors. Participants' experiences with the intervention helped to identify areas for future intervention refinement. Future quantitative work is needed to corroborate these qualitative findings and assess the efficacy of the intervention on long-term physical activity engagement. Trial Registration: This trial is registered in Clinical Trials.gov, ID number NCT01551953.

A Tai Chi Class Collaboratively Developed for Persons With Interstitial and Other Lung Diseases: An Ethnographic Investigation.

Background: Participating in physical activity (PA) can be challenging for persons with chronic and significant lung disease due to the multifaceted disruptive effects of their symptoms and variable disease course. Objectives: Our study investigates a novel approach to increasing PA by collaboratively and adaptively developing a Tai Chi (TC) class for and by persons with lung diseases and explores participants' perceptions of their experiences in the co-developed TC class. Methods: We initiated a collaboration between the Interstitial Lung Disease (ILD) Collaborative and the Tai Chi Foundation to develop a TC class appropriate for persons with ILD and other lung diseases. The TC class was offered online, during the early phases of the COVID-19 pandemic, when pulmonary patients were isolated socially. TC class sessions were held twice weekly for 12 weeks with 12 participants. Ethnographic field methods were used to collect observations and conduct interviews with teachers and students. The Social Ecological Model (SEM) for understanding factors in intrapersonal, interpersonal, social, and organizational contexts was used to explore ways in which wellness practices, particularly those involving changes in health behaviors, can be collaboratively conceived, and developed by persons with the lived experience of illness and community organizations that are sensitive to their personal and social contexts. The constant comparative method was used for data analysis. Results: Our findings include the importance of (1) creating a supportive class environment, characterized by interactive and reciprocal relationships among students and teachers; (2) alternating segments of movement and meditation to avoid fatigue and breathlessness; (3) cultivating sensory awareness and body trust, resting when needed and rejoining the movements when ready; (4) increasing the capacity to meditate through deepening presence and renewing the vital connection with inner and outer sources of energy; (5) reducing, through meditative movement, the persistent anxiety, isolation, and sense of loss that accompany chronic disease diagnosis and progression. Conclusion: We documented a collaboration between the TC and pulmonary communities to design a TC class for persons with chronic and significant lung disease. We employed the SEM to provide insights into how teachers, informed by their students, can use effective pedagogical skills to create core curricula with modifications appropriate for a specific population.

Longitudinal Care Patterns and Utilization Among Patients With New-Onset Neck Pain by Initial Provider Specialty.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To compare utilization patterns for patients with new-onset neck pain by initial provider specialty. SUMMARY OF BACKGROUND DATA: Initial provider specialty has been associated with distinct care patterns among patients with acute back pain; little is known about care patterns among patients with acute neck pain. METHODS: De-identified administrative claims and electronic health record data were derived from the Optum Labs Data Warehouse, which contains longitudinal health information on over 200M enrollees and patients representing a mixture of ages and geographical regions across the United States. Patients had outpatient visits for new-onset neck pain from October 1, 2016 to September 30, 2019, classified by initial provider specialty. Utilization was assessed during a 180-day follow-up period, including subsequent neck pain visits, diagnostic imaging, and therapeutic interventions. RESULTS: The cohort included 770,326 patients with new-onset neck pain visits. The most common initial provider specialty was chiropractor (45.2%), followed by primary care (33.4%). Initial provider specialty was strongly associated with the receipt of subsequent neck pain visits with the same provider specialty. Rates and types of diagnostic imaging and therapeutic interventions during follow-up also varied widely by initial provider specialty. While uncommon after initial visits with chiropractors (≤2%), CT, or MRI scans occurred in over 30% of patients with initial visits with emergency physicians, orthopedists, or neurologists. Similarly, 6.8% and 3.4% of patients initially seen by orthopedists received therapeutic injections and major surgery, respectively, compared with 0.4% and 0.1% of patients initially seen by a chiropractor. CONCLUSION: Within a large national cohort, chiropractors were the initial provider for a plurality of patients with new-onset neck pain. Compared with patients initially seen by physician providers, patients treated initially by chiropractors or therapists received fewer and less costly imaging services and were less likely to receive invasive therapeutic interventions during follow-up. LEVEL OF EVIDENCE: 3.

The impact of neck pain on gait health: a systematic review and meta-analysis.

BACKGROUND: Evidence exists demonstrating the negative impacts of chronic musculoskeletal pain on key measures of gait. Despite neck pain being the second most common musculoskeletal pain condition, there is a paucity of evidence exploring the impacts of neck pain specifically on these outcomes. The aims of this work were to systematically review the current evidence of the associations between chronic neck pain and measures of gait health and to conduct meta-analysis for quantitative assessment of the effect sizes under different walking conditions. METHODS: Systematic review was conducted following PRISMA guidelines. Databases searched included MEDLINE, Embase, Web of Science, CINAHL, and PEDro. Eligible study designs included observational studies consisting of an exposure group with chronic neck pain and control group without chronic neck pain and primary outcomes relating to gait health. For outcomes amenable to meta-analysis, a random-effects model was used to derive summary estimates of Hedge's g depicted graphically with forest plots. Other gait outcomes were narratively summarized. Risk of bias was also assessed. RESULTS: The original search yielded 1918 articles; 12 met final eligibility criteria including 10 cross-sectional studies. Outcomes were grouped first by the five domains of gait: pace, rhythm, asymmetry, variability, and postural control; and second by the tested walking conditions. Meta-analyses for gait speed revealed large effect-sizes indicating that individuals with chronic neck pain had slower measures of gait and lower measures of cadence. Gait outcomes that were narratively summarized supported these findings. CONCLUSION: The quantitative and qualitative findings of this systematic review and meta-analysis suggest a negative impact of CNNP on measures of gait health, particularly gait speed, under various walking conditions. However, broad interpretation of these results should be cautious. Testing gait under dual task conditions may be particularly sensitive to the impact of CNNP, and future work is needed to better understand how pain disrupts this important functionality of the locomotor system. Additionally, consideration should be made to assess measures of variability and investigate these relationships in the older adult population.

Is Tai Chi beneficial for multisite pain syndrome in older adults?

Chronic musculoskeletal pain is prevalent and undertreated in older adults. In particular, multisite pain is associated with serious functional consequences and falls and appears to be a novel geriatric syndrome. The causes of multisite pain are often multifactorial, and emerging evidence supports a complex pathway whereby multisite pain leads to cognitive problems, mobility decline, fear of falling, falls, and reduced participation in life roles. A few pharmacologic approaches are safe and effective for older adults with chronic multisite pain and evidence for effectiveness of non-pharmacologic treatments for this common condition is very limited. Compared to light physical exercise, mind-body exercise may prove to be more beneficial for older adults living with chronic pain. Tai Chi, as a movement-based mind-body exercise, can relieve pain symptoms, improve cognition and physical function, and lower risk for falls in older adults. However, little is known about the potential benefits of Tai Chi for older adults with multisite pain syndrome. Future large-scale randomized-controlled trials are needed to investigate the effectiveness of Tai Chi in alleviating pain and lowering fall risk in older adults with multisite pain, and the biological mechanisms that underlie its potential benefits to chronic pain, physical and cognitive functions, and falls in this at-risk population.

Pilot studies of recruitment and feasibility of remote Tai Chi in racially diverse older adults with multisite pain.

BACKGROUND: Multisite musculoskeletal pain is highly prevalent among older adults yet undertreated. Studies support the promise of Tai Chi for managing pain and lowering fall risk. Since the COVID-19 pandemic, effective alternatives to classroom-based exercise programming are warranted. AIMS: To recruit 100 racially diverse older adults with multisite pain and increased fall risk, who are interested in participating in a future Tai Chi clinical trial, and to evaluate the feasibility and acceptability of a short-term, remotely delivered home-based Tai Chi program. METHODS: A random sample of adults aged 65 years or older living in diverse Boston neighborhoods were sent mailed invitations to participate in a telephone screening survey. Eligible adults were invited to join a 4-week Tai Chi program offered online via Zoom. Primary outcomes were class attendance, experience, and program safety. RESULTS: Among 334 survey respondents, 105 were eligible for the intervention. Average age of eligible participants was 74 years, 75% were women, and 62% were Black. We assigned 32 participants to 4 Tai Chi or 2 light exercise groups conducted via Zoom; of these, 24 (75%) completed the program and 79% attended ≥6 of 8 classes. There were no adverse events reported. Two-thirds reported it was very easy to join the online classes and 88%, very easy to see the instructor. CONCLUSION: Mailed invitations were effective for recruiting a racially diverse sample. Remote exercise programming delivered online via live Zoom sessions is safe and feasible for diverse older adults who have multisite pain and risk of falls.

Day-night patterns in heart rate variability and complexity: differences with age and cardiopulmonary disease.

STUDY OBJECTIVES: Heart rate variability (HRV) measures provide valuable insights into physiology; however, gaps remain in understanding circadian patterns in heart rate dynamics. We aimed to explore day-night differences in heart rate dynamics in patients with chronic cardiopulmonary disease compared with healthy controls. METHODS: Using 24-hour heart rate data from patients with chronic obstructive pulmonary disease (COPD) and/or heart failure (n = 16) and healthy adult controls (older group: ≥50 years, n = 42; younger group: 20-49 years, n = 136), we compared day-night differences in conventional time and frequency domain HRV indices and a multiscale-entropy-based complexity index (CI1-20) of HRV among the 3 groups. RESULTS: Twenty-four-hour HRV showed significant day-night differences (marked with "△") among younger healthy (mean age: 34.5 years), older healthy (mean age: 61.6 years), and cardiopulmonary patients (mean age: 68.4 years), including change in percentage of adjacent intervals that differ > 50 ms (△pNN50), high frequency (△HF), normalized low frequency (△nLF), ratio (△LF/HF), and △CI1-20. Among these, △LF/HF (2.13 ± 2.35 vs 1.1 ± 2.47 vs -0.35 ± 1.25; P < .001) and △CI1-20 (0.15 ± 0.24 vs 0.02 ± 0.28 vs -0.21 ± 0.27; P < .001) were significant in each pairwise comparison following analysis of variance tests. Average CI1-20 was highest in younger healthy individuals and lowest in cardiopulmonary patients (1.37 ± 0.12 vs 1.01 ± 0.27; P < .001). Younger healthy patients showed a heart rate complexity dipping pattern (night < day), older healthy patients showed nondipping, and cardiopulmonary patients showed reverse dipping (night > day). CONCLUSIONS: As measures of 24-hour variability, traditional and complexity-based metrics of HRV exhibit large day-night differences in healthy individuals; these differences are blunted, or even reversed, in individuals with cardiopulmonary pathology. Measures of diurnal dynamics may be useful indices of reduced adaptive capacity in patients with cardiopulmonary conditions. CITATION: Ma Y, Chang M-C, Litrownik D, Wayne PM, Yeh GY. Day-night patterns in heart rate variability and complexity: differences with age and cardiopulmonary disease. J Clin Sleep Med. 2023;19(5):873-882.